Sony may have more work to do to jumpstart service to its PlayStation Network.

The entertainment and electronics giant announced yesterday that its entire portfolio of online games, game forums, and Web sites would go back online today. After service resumed, however, users started complaining on Twitter that it wasn't active long before it was unavailable again.

"Playstation Network was back up for about 10 minutes before going down again for maintenance," Tom Cranfield tweeted. "Nice work Sony!"

"Playstation Network is Back down looks like the servers have crashed," Lee Fraser of Manchester, England, said in a Twitter post.

Sony's PlayStationEU twitter feed asked users to be patient.

"Please bear with us as we continue working on #PSN restoration. We are experiencing extremely heavy traffic," the feed said.

Sony later announced a planned outage of its network services.

"We're expereiencing [sic] a heavy load of password resets and will be turning off the services for 30 minutes to clear the queue," the company announced on its Twitter page.

The service had been offline for nearly four weeks after several of Sony's servers were attacked between April 17 and April 19, leading to the exposure of the personal data of more than 100 million customers who signed up for PlayStation Network, Qriocity, and Sony Online. The networks--used for downloading and playing games, movies, and music--were mysteriously unavailable for nearly a week before Sony revealed the intrusion. The company has said repeatedly that there is no evidence that credit card information was stolen.

Sony said its network services would be unavailable while it beefed up its security and announced earlier this week that it planned to restore them "in the next few days." The company has still has not identified the perpetrator behind the second-largest security breach in U.S. history, but has hinted it believes the hacker activist group Anonymous may have been behind the breach.